Abstract
We show that the uncertainty in the relative quantum phase of two fields propagating in the arms of a Mach-Zehnder interferometer can be reduced to the Heisenberg limit by driving the interferometer with two Fock states containing equal numbers of photons. This leads to a minimum detectable phase shift far below that of any interferometer driven by a coherent light source.
- Received 25 January 1993
DOI:https://doi.org/10.1103/PhysRevLett.71.1355
©1993 American Physical Society